Conventional condensers for use in various kinds of cooling devices which generate cold water and ice have been known. For example, Patent Document 1 below discloses an example of such condensers. The condenser according to Patent Document 1 is connected to a discharge portion of a compressor, and an evaporator is connected to a suction portion of the compressor, where vapor generated when cold water is cooled down in the evaporator is sent to the condenser by the compressor in order to condense the vapor in the condenser. The condenser is configured to shed cooling water from an upper space in its housing in a shower form, and cause the vapor to adhere to the cooling water which turned into a mist in a lower space in order to condense the vapor. The condenser is provided with a degassing mechanism in order to improve condensation efficiency of vapor.
That is, if much air is included in cooling water to be shed in the housing, the air will hinder condensation of vapor adhering to the cooling water, so that air content of the cooling water is decreased by degassing air in the housing by a degassing mechanism. To be more specific, a plurality of degassing chambers vertically divided by a screen plate is provided in the housing. Cooling water shed from an upper space in the housing is accumulated on the screen plate in the upper degassing chamber to form a water film which separates the upper and lower degassing chambers from one another, and the cooling water is shed in the lower degassing chamber in a shower form by passing through fine holes of the screen plate. The condenser is provided with a first degassing device for discharging air degassed from the lower degassing chamber to the upper degassing chamber, and a second degassing device for externally exhausting air degassed from the upper degassing chamber. The first degassing device concentrates air by removing water contained in air degassed from the lower degassing chamber in order to discharge the air to the upper degassing chamber, while the second degassing device further concentrates air by removing water contained in air degassed from the upper degassing chamber in order to externally exhaust the air. Air is thus concentrated and degassed in two stages by the first degassing device and the second degassing device, so that a load applied to each of the degassing devices is reduced.
In the above condenser disclosed in Patent Document 1, pressure in the lower degassing chamber is decreased when a temperature in the lower degassing chamber is decreased due to various kinds of causes such as an operation state of the compressor, where a pressure difference of the upper degassing chamber relative to the lower degassing chamber is increased. In this case, a water level of cooling water accumulated on the screen plate is decreased in the upper degassing chamber, where a water film of cooling water for separating the upper and lower degassing chambers from one another is removed, and there is the danger that the upper and lower degassing chambers will communicate with one another. If the upper and lower degassing chambers thus communicate with one another, the first degassing device for concentrating and discharging air from the lower degassing chamber to the upper degassing chamber stops functioning.
Patent Document 1: National Publication of Translated Version No. 2003-534519.